Mitchell 805 kit to be RC

[davidchoate]

I got My B-25, and looked over the plans. Since it was designed for twin .049's control line, ans has moveable controls on the plans; I think it was a god choice to do a twin motor. I need help though. I have no idea how to wire up twin motors. Hope I can can get help from someone who has done it. And I was hoping for help with what to set the thrust angles, and etc. at. It has this on the plans, but its for control line flying. I dont even know which is #1 motor, or which way the props should rotate. Help? Also there are instructions on how to make pin holes and use the cardboard control surfaces. Is this to simulate rivets? And lastly, though not a laser cut kit, The wood is very nice, and die cut to where it falls out of the sheet as if it were. I am very pleased with the Quality, xcept I prefer plywood instead of that polystyrene firewall stuff, but thats no big deal.. I also have the PT-17 laser cut from Dale last Christmas I have to finish. So I may do that while in the planning/research stage of the B-25.

[Bill Gaylord]

This is one model I'd like to build for r/c. It's on the "one of these days" list. I built one in the past, but it's too heavy to be practical for r/c. Done again I'd probably cheat the span and maybe the chord a bit. Definitely doable, but difficult to build light with all the heavy plastic parts. I remember having to add a former shim on the wing bases to move the engines out a bit. With 6" props the fuse side guns still had to be cut short so that the props didn't cut into them. The biggest hangup with this model is that it's just a bit small for practicality, but then again that's what makes it challenging. 30" span would be much easier. For thrustline settings I would just try to set them as straight as possible. Twins are tricky enough to do that with, let alone setting thrust angles. I've never had a problem with them as long as they are pretty much dead on. It doesn't take much error to really throw off the way the model flies.

For a first conversion, I would definitely not want to start with the B25. The DC3 (C47) is rarely done, but is a much more practical subject and a good flyer. The model surprised me by flying both well and slow at 19+ oz with relatively low power outrunners. It has a slight span cheat, but done again I could have easily built it a bit lighter with the scale span.

[davidchoate]

Thanks Bill. Thats another reason I'd like to make a replica Doolittle B-25. Strip it to the bone. No gons.. And I may be able to omit some plastic . I have gotten some experience now wetting and shaping balsa. I'm using your PT-17 thread on Wattflyer as a guide for My PT-17 build. What motor and propworked best for you with that. ?

[Bill Gaylord]

I'll often use what I have if it's in the ballpark, whether 100% ideal or not. I believe that motor was roughly a 1400kv 300 class motor and an 8x4 Master Airscrew prop. The specs of these motors are not always 100% accurate either. When possible I prefer a reasonably scale sized prop, which isn't always the most efficient but as long as it flies reasonably well it's good enough. It's all trade offs. The Stearman setup was probably a pretty ideal setup though.

The Doolittle would be a nice B25 project. If I ever get around to one, it will probably be a scratch build since there's only a few kits around the 36"-40" span that I seem to like. The few kits like the Dumas and Dare are on the opposite end of the Guillows, in that they're a bit fragile in some areas. Kits don't exactly always give consistent wood of reasonable strength also. By the time you rework the areas deemed necessary, it's almost as easy to just start from scratch. There's definitely some advantages to building with your own modifications or design where you can make whatever areas you deem necessary robust, using wood specifically selected for each area. If you watch some of the videos I've done at the park field with tall weeds and grass, I try to land as softly as possible, but they basically just plow into the tall weeds. I have yet to damage one on landing beyond maybe a cracked stab. I would not want to try that with something like a Dumas B25 built stock, from the kit wood.

[davidchoate]

I could go to Staples, and enlarge the plan slightly, by a couple inces, but like you said, it'd be easier to just ordr a plan ,or get one of those taped together ones free as the plastic parts wont fit. I can sheet the wungs and stuff to add strength I guess. Fly RC has a build Guy who is a Master ,and converts these things to powered flight. It's usually a 3 or 4 part article. Rught now He's doing a B-17 about the same size as Guillows. He did a Dumas Aeronca 300 series, and I got that kit. So the article will Be VERY helpful to Me.I do have a nice 300 brushless with ESC and a E-flite 370 4100kv inrunner with gearbox I am not sure which is better to use yet. I am doing the plastic now just to get it out of the way, as I hate working with plastic. But I'm going all out with the engine detail. As a mechanic; I feel its only right.LOL

[davidchoate]

Some Doolittle Pics.

[davidchoate]

I watched a show today about the doolittle Raid. Those planes were stripped down. They even replaced the rear 50's with broom sticks painted black to fool any Zeros to think them armed, had one less crewman , and a lighter bombload. They needed the weight in fuel more than weaponry.

[Chris A.]

For greater detail on the Doolittle Raid, I recommend the new book "The Aviators" which is the flying history of Doolittle, Rickenbacher and Lindberg. Excellent read although there are some text mistakes.

[davidchoate]

Thanks Chris. I Love History. Bill I agree. I have a couple Dumas kits, but never built one. I as well noticed that ,though light, some wood is, and especially stringers, very very brittle, Like a straw twig. I Like the light construction, but really gotta find the right one to make RC. They do have a few kits to be electric RC right from the plans, but then thats just too easy. And I am also a fan of your videos Bill. If not for them, honesly, I may have given up on believing these things can fly. I'm so close to a complete success, I can taste it.

[Bill Gaylord]

I have to admit I'm a fan of reasonably heavy stringers. The Dumas stringers have not worked well for me. Thanks to Guillows models, I still have a few sheets of strong stringers on hand, but am running low. Just seems like one area not worth skimping on, when weight can be effectively saved in other areas. When I've used light stringers and managed to not break them, then the covering bows them inward after shrinking and the model doesn't look right.

I appreciate the video comment David. One of the reasons I put them up is that other people's videos really motivated me when I got started. I'd have to watch them sometimes to keep up the motivation. There's something about actually seeing the model built and fly that really helps. The same thing goes for a few scratch builders that built some of the odd stuff that I got into. Their build threads were real motivators for me.